牛奶中特定益生菌菌株的生长与代谢

Growth and metabolism of selected strains of probiotic bacteria in milk.

作者信息

Østlie Hilde M, Helland Merete H, Narvhus Judith A

机构信息

Department of Food Science, Agricultural University of Norway, P.O. Box 5036, N-1432, As, Norway.

出版信息

Int J Food Microbiol. 2003 Oct 15;87(1-2):17-27. doi: 10.1016/s0168-1605(03)00044-8.

DOI:10.1016/s0168-1605(03)00044-8

PMID:12927703

Abstract

Growth and metabolism of five probiotic strains with well-documented health effects were studied in ultra-high temperature (UHT) treated milk, supplemented with 0.5% (w/v) tryptone or 0.75% (w/v) fructose. The probiotic strains were Lactobacillus acidophilus La5, Lb. acidophilus 1748, Lactobacillus rhamnosus GG, Lactobacillus reuteri SD 2112 and Bifidobacterium animalis BB12. Fermentation was followed for 72 h at 37 degrees C and the samples were analysed for pH, log cfu ml(-1), volatile compounds, organic acids and carbon dioxide. The strains reduced pH from 6.7 to between 3.9 and 4.4 after 24 h of incubation. All strains attained viable cell counts above 8.7-9.18 log cfu ml(-1) after 6-16 h of incubation. The two Lb. acidophilus strains showed a stable level of viable cells during 12-72 h of incubation but the three other strains showed a reduction of 0.4-1.1 log cfu ml(-1) from 24 to 72 h of incubation. However, all strains showed cell levels between 7.8 and 8.7 log cfu ml(-1) after 72 h of incubation. After 48 h of incubation, the amount of lactic acid produced varied according to strain from 6949 to 14,000 mg kg(-1) and acetic acid produced varied from 0 to 6901 mg kg(-1). Three of the strains metabolised citrate but only low amounts of diacetyl and acetoin were detected within strains, 0.2-0.8 and 6.5-10 mg kg(-1), respectively. Carbon dioxide produced varied from 221 to 3942 mg kg(-1) and was connected to the citrate-fermenting ability of the strain used and their carbohydrate fermentation pathway. Three of the strains produced detectable levels of acetaldehyde and the concentration varied from 9.4 to 12.6 mg kg(-1) after 24 h of incubation. All five probiotic strains showed very different profiles of metabolites during fermentation; however, the two Lb. acidophilus strains were the most alike. Our findings show the importance of controlling the fermentation time since the probiotic strains produced different amounts of metabolic products according to fermentation time.

摘要

研究了5种具有充分文献记载的健康功效的益生菌菌株在超高温（UHT）处理的牛奶中的生长和代谢情况，牛奶中添加了0.5%（w/v）胰蛋白胨或0.75%（w/v）果糖。益生菌菌株分别为嗜酸乳杆菌La5、嗜酸乳杆菌1748、鼠李糖乳杆菌GG、罗伊氏乳杆菌SD 2112和动物双歧杆菌BB12。在37℃下发酵72小时，对样品进行pH值、每毫升菌落形成单位对数（log cfu ml⁻¹）、挥发性化合物、有机酸和二氧化碳的分析。孵育24小时后，菌株将pH值从6.7降低到3.9至4.4之间。孵育6至16小时后，所有菌株的活菌数均达到8.7 - 9.18 log cfu ml⁻¹以上。两株嗜酸乳杆菌在孵育12 - 72小时期间活菌水平稳定，但其他三株菌株在孵育24至72小时期间活菌数减少了0.4 - 1.1 log cfu ml⁻¹。然而，孵育72小时后，所有菌株的细胞水平均在7.8至8.7 log cfu ml⁻¹之间。孵育48小时后，不同菌株产生的乳酸量在6949至14000 mg kg⁻¹之间变化，产生的乙酸量在0至6901 mg kg⁻¹之间变化。其中三株菌株代谢柠檬酸盐，但菌株内仅检测到少量的双乙酰和乙偶姻，分别为0.2 - 0.8和6.5 - 10 mg kg⁻¹。产生的二氧化碳量在221至3942 mg kg⁻¹之间变化，且与所用菌株的柠檬酸盐发酵能力及其碳水化合物发酵途径有关。其中三株菌株产生了可检测水平的乙醛，孵育24小时后浓度在9.4至12.6 mg kg⁻¹之间变化。所有五株益生菌菌株在发酵过程中表现出非常不同的代谢产物谱；然而，两株嗜酸乳杆菌最为相似。我们的研究结果表明控制发酵时间很重要，因为益生菌菌株根据发酵时间产生不同量的代谢产物。